INTRODUCTION: Amiodarone (AMD) is an antiarrhythmic agent which contains 37% of iodine. It can reach the fetus by transplacental passage and induce transient congenital hypothyroidism (TCH). We report two cases of TCH caused by gestational exposure to AMD, detected by the Newborn Screening Program for Congenital Hypothyroidism of the State of Paraná – Brazil. CLINICAL CASE 1 (C1): Neonatal TSH value was 78,2mU/L (normal < 15 mU/L). AMD had been given to the mother during pregnancy to treat maternal arrhythmia. […]